Fire-door draft-check.



R. G. LONG. FIRE DOOR DRAFT CHECK. APPLICATION FILED SEPT. 19, 1913.

1,093,446. Patented Apr. 14, 1914.

2 SHEETS-SHEET 1.

COLUMBIA PLANDGRAPH c0., WASHINGTON, D. c.

R. G. LONG.

FIRE DOOR DRAFT CHECK.

APPLIUATION FILED SEPT. 19, 1913.

1 ,09 3 ,446, Patehted Apr. 14, 1914.

2 SHBETSSHEET 2.

* ED STATES PATENT oinucn.

ROBERT G. LONG, 01: LAWRENCE, KANSAS.

FIRE-DOOR DRAFT-CHECK.

To all whom it may concern Be it known that I, ROBERT G. LONG, a citizen of the United States, residing at Lawrence, in the county of Douglas and State of Kansas, have invented new and useful Improvements in Fire-Door Draft- Ohecks, of which the following is a specification.

This invention has relation to fire door draft checks and it consists in the novel features hereinafter described and claimed.

An objectionable feature of furnaces of the force draft type is the belching forth or shooting out of gas through the fire door when the fuel is added. This is due to the excessive amount of gas formed by the fine particles of fuel added, igniting more rapidly, while the condition with the pres sure underneath the grate and the draft, or vacuum above the fuel bed are balanced. To overcome this objectionable feature it is necessary to reduce the pressure underneath the fuel bed momentarily when the fire door is opened to allow the over draft to become great enough to carry off the excessive gas. In the present instance the draft check is automaticaly operated by the opening and closing of the fire door and when the door is opened the draft under the fire is closed or partly closed and when the door is closed the damper or draft under the fire bed is opened or returned to its normal position to supply the fuel with oxygen or air.

lVhile the device herein shown and described is designed primarily to be auto matically operated by the swinging of the fire door the device is susceptible of being operated manually while the fire door is in open or closed position.

In the accompanying drawing :Figure 1 is a front elevation of a portion of a furnace showing the door draft check applied. Fig. 2 is a transverse sectional view of the same showing the position of the parts when the damper is closed or partially closed. Fig. 3 is a similar view showing the positions of the parts when the damper is in an open position. Figs. 4 and 5 are sectional detailed views of modified forms of the arrangement of the parts of the draft control.

As illustrated in the accompanying drawing the furnace 1 is provided with the usual fire doors 2 and grate 3. An air duct 4 leads up through the ash pit and has its discharge end below the grate 3. A shaft Specification of Letters Patent.

Application filed September 19, 1913.

Patented Apr. 14, 1914:. Serial No. 790,728.

5 is journaled in the said air duct and is provided with a damper 6 which may be swung or turned as the shaft is rotated to completely or partially close the said air duct. A pulley 7 is fixed to the shaft 5 and is located in front of the front wall of the furnace 1. A weight 8 is mounted upon the pulley 7 at one side of the center and is so disposed that when the said Weight is vertically under the center of the shaft 5 the damper 6 is held in an open position in the air duct 4:.

Bracketsf) are mounted upon the front wall of the furnace 1 above the fire doors 2 and the said brackets are provided with bearings 10 in which a shaft 11 is journaled. Collars 12 are fixed to the shaft 11 and bear against the inner ends of the bearings 10 and serve to prevent the shaft 11 from moving longitudinally in these bearings. The collars 12 are provided at their outer sides with lugs 18 which are adapted to encounter the sides of the brackets 9 when the shaft is turned and consequently the said lugs limit the turning movement of the shaft in the bearings 10. Blocks 14 are fixed to the end yortions of the shaft 11 and the said blocks are provided at their lower ends with recesses 15 in which pawls 16 are pivotally mounted. The lower end portions of the said pawls project below the lower edges of the blocks 14: and the said pawls lie in the paths of movement of lugs 17 carried at the free edge portions of the fire doors 2.

A handle lever 18 is fixed to the intermediate portion of the shaft 11 and one end of a crook shaped member is pivotally connected with the said handle lever at a point above the axis of the shaft 11. A chain or flexible member 20 is connected at one end with the lower end of the said crook shaped member 19 and the lower end of the said member 20 is fixed to the periphery of the pulley 7. The parts are so arranged that the point of pivotal connection between the crook shaped member 19 and the handle lever 18 may swing beyond one side or the other of the vertical center of the shaft 11. When the parts are in the position as shown in Fig. 3 the fire doors 2 are closed and the damper 6 is open. When one of the fire doors 2 is swung to an open position the lug 17 carried thereby encounters the pawl 16 opposite the same and inasmuch as the pawl 16 bears against one end of the recess 15 the block let is turned and the shaft 11 is partially rotated and the handle lever 18- is swung. This carries the point of pivotal connection between the crook shaped lever 19 and the handle lever 18 in an upward direction and over and beyond the vertical line passing through the center of the shaft 11 so that the flexible member 20 is moved longitudinally and the pulley 17 is partially rotated. This movement on the part of the said pulley turns the shaft 5 which in turn swings the damper 6 to a closed or partly closed position in the air duct 4. Thus it will be seen that when the fire door 2 is opened the damper 6 is moved to a position in the air duct to check the under draft and consequently the suction created through the chimney or flue will cause the air to pass in through the opening for the door 2 over the fire and this will prevent the gases from gushing or shooting out the front of the furnace.

hen the fire door 2 is swung to a closed position the lug 17 carried thereby encounters the pawl 16 and inasmuch as the pawl is then bearing against the opposite end of the recess 15 the block 14: and shaft 11 are turned in a direction opposite to that just above described and the crook shaped member 19 is returned to the position as shown in Fig. 3. At the sametime the weight 8 gravitates and turns the pulley 7 and the shaft 5 whereby the damper 6 is moved to an open position in the air duct 4 and the under or force draft through the fire grateis reestablished.

In Fig. 1 of the drawing'it will be seen that two fire doors 2 are arranged to operate a single draft check device and it is obvious that when either one of the doors 2 is open the damper 6 will be partially closed and when the said door 2 is moved to a closed position the damper 6 is automatically opened.

When it is desired to move the damper 6 when the doors 2 are closed or opened it may be readily accomplished by an operator using the handle lever 18 and by reason of the arrangement of the parts above de scribed the free end of the said lever Wlll remain at either side of the vertical line passing through the center of the shaft 11.

after the said lever has been manually swung as above indicated.

In the arrangement of the parts as illustrated in Fig. 5 it will be seen that the flexible member 20 is trained under a loosely j ournaled pulley 21 and extends back to the damper 22 which is pivotally mounted in th bridge wall of the furnace.

In the arrangementof parts as illustrated in Fig. 4 it will be seen that the flexible member 20 is attached to a gear wheel 23 which in turn is weighted at one side and the said gear wheel 23 meshes with a gear wheel 24 fixed to the upper end of a vertically disposed shaft 25. The shaft 25 carries a damper 26 which is located in an air duct 27 which leads under the grate of the furnace.

Having described the invention what is claimed is In combination w1th a furnace havlng a plurality of fire doors and a damper, a draft check comprising a shaft journaled upon the furnace, a handle lever fixed to theshaft, a member pivoted to the handle lever and arranged to move so that the point of pivotal connection between the said'member and the handle lever may be carried from one side to the other of a vertical line passing through the center of the shaft, a flexible member connected with the said pivoted member and the damper, blocks fixed to the shaft and corresponding in number to the number of fire doors, each block having a recess, a pawl pivoted in each recess and projecting into the path of movement of one of the fire doors.

In testimony whereof I aflix my signature in presence of two witnesses. 7

ROBERT e. LONG.

\Vitnesses v HUGH MEANS, RAYMOND F. Bron.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

